1. Field of the Invention
The present invention relates to an electrophotography apparatus for exposing a photosensitive body using a line head comprising an array of a large number of light-emitting elements.
2. Description of the Related Art
As a light-emitting element of this type, an EL (electroluminescence) element, or the like is known. For example, a printer called an EL printer, employs a line head comprising an array of a large number of EL elements to perform information recording on a photosensitive drum. More specifically, after the surface of the photosensitive drum, which surface is formed of a photoconductive material, is uniformly charged, the surface is exposed by light emitted from the EL elements, thereby recording image information in the form of an electrostatic latent image. The electrostatic latent image is developed with toner, and the toner image is transferred onto a paper sheet, thus performing a printing operation.
In an EL printer of this type, when EL elements cause an operation error, a nonuniformity or omission in printed data may occur, resulting in low printing quality. For this reason, the defective EL elements must be detected. In a conventional apparatus, all the EL elements of the line head are caused to emit light to perform a printing operation, and an error position is detected on the basis of a printed state.
However, when the defective EL elements are checked by performing a printing operation, the checking operation takes much time, and the defective EL elements may often be overlooked due to visual confirmation.